Roques et al. (Nature Vol. 288, November 1980, p. 286-288) disclose that thiorphan, (DL-3-mercapto-2-benzylpropanoyl)-glycine, is an inhibitor of enkephalinase in vitro in nanomolar concentration and in vivo after either intracerebroventricular or systemic administration.
Ondetti et al. in U.S. Pat. No. 4,053,651 discloses that various mercaptoalkanoyl amino acids are useful hypotensive agents due to their ability to inhibit the angiotensin converting enzyme.
Sundeen et al. in U.S. Pat. No. 4,235,885 disclose that mercaptoalkanoyl amino acids of the formula ##STR2## wherein R.sub.2 can be an amino acid are useful in the treatment of rheumatoid arthritis due to their mammalian collagenase inhibitory activity.